4-Androstenediol is a metabolite of testosterone. Conversely, the conversion of 4-androstenediol to testosterone has been demonstrated to occur in homogenates of hyperplastic human female adrenal glands. 4-Androstenediol is an anabolic agent that has been found in increased concentration in athletes suspected of doping. 4-Androstenediol has also been found in aqueous and solid nutritional supplements that are commercially available. Studies showing that non-hormonal supplements such as vitamins, minerals, and amino acids can contain anabolic androgenic steroids not declared on the labels of the products have been published. These undeclared substances (often prohormones of testosterone) can cause health risks to consumers and might lead to positive results in sports doping control. It has been demonstrated that 4-androstenediol taken by mouth is capable of producing in vivo increases in testosterone concentration in apparently healthy young men an women.